In a wireless communication network, a terminal may support two radio bearer (RB) types, i.e., a first bearer type and a second bearer type, wherein, under the first bearer type, the terminal receives data packets of radio bearers only from a first base station, under the second bearer type, the terminal receives the data packets of the radio bearers from the first base station and a second base station at the same time.
Presently, in a procedure of a radio bearer converting from the second bearer type to the first bearer type, a method of reordering received data packets by a packet data convergence protocol (PDCP) entity relevant to the radio bearer in the terminal is: the PDCP entity keeps reordering the received data packets until a lower edge of a reordering window is larger than a serial number m, the PDCP entity stops reordering the data packets, wherein, the lower edge of the reordering window is a serial number of the earlier data packet among all data packets which are still considered for reordering; the serial number m is a largest serial number of a data packet received by the PDCP entity before a radio link control (RLC) entity is released, wherein, the RLC entity is associated with the radio bearer and corresponds to the second base station.
However, the data packet corresponding to the largest serial number received by the PDCP entity before the RLC entity is released is not always the last data packet which needs to be reordered, therefore, the above technical solution leads to the PDCP entity in the terminal stopping reordering data packets prematurely, thereby the disordering of the data packets sent to an upper layer by the PDCP entity may appear.